Power transistors commonly employed in automotive and industrial electronics require a low on-state resistance (Ron A), while securing a high voltage blocking capability. For example, a MOS (“metal oxide semiconductor”) power transistor should be capable, depending upon application requirements, to block drain to source voltages Vds of some tens to some hundreds or thousands of volts. MOS power transistors typically conduct very large currents which may be up to some hundreds of Amperes at typical gate-source voltages of about 2 to 20 V. Low-voltage power transistors are applied in a drain to source voltage range Vds below 10 Volts.
Lateral power devices, in which a current flow mainly takes place parallel to a first main surface of a semiconductor substrate, are useful for integrated circuits in which further components, such as switches, bridges and control circuits are integrated. Generally, transistors are being investigated which may be used as a low-resistive low-voltage power switch and which may be integrated with a driver circuit.
Accordingly, it is an object of the present invention to provide an improved semiconductor device meeting the above-defined demands. Further, it is an object to provide a method for manufacturing such a semiconductor device.